Aircraft regulatory agencies such as the Federal Aviation Administration (FAA) typically require aircraft manufacturers to demonstrate that an aircraft meets certain performance and safety requirements prior to certification of the aircraft. Aircraft manufacturers typically perform a series of flight tests in a flight test program designed to demonstrate the performance and safety requirements of the aircraft. During flight testing of an aircraft, one or more ballast tanks may be installed in the aircraft. The ballast tanks may be filled with water to provide ballast for simulating the mass of passengers, cargo, or other equipment that may be carried by the aircraft during normal operations.
During a flight test, an aircraft may undergo directional changes in the flight path due to pilot-initiated maneuvers and/or due to turbulence encountered by the aircraft. The directional changes in the aircraft flight path may cause water in the ballast tank to temporarily move toward one side of the tank. The movement of the water within the ballast tank and corresponding shift in the center of gravity (CG) of the water may cause a shift in the aircraft CG. In order to maintain stability during flight, the CG of an aircraft must typically be maintained within a predetermined CG offset limit as may be established by the aircraft manufacturer.
For different parts of a flight testing program for an aircraft, the ballast tank may be filled to different levels prior to takeoff to simulate different amounts of mass that may be carried by the aircraft. When a conventional ballast tank is filled to either a relatively low level or a relatively high level, the CG shift of the water may be relatively small such that the shift in the aircraft CG may be maintained within the established CG offset limit. However, when the conventional ballast tank is filled to an intermediate level, the CG shift of the water may be relatively large causing the aircraft CG to exceed the established CG offset limit.
As can be seen, there exists a need in the art for a system and method for controlling the CG shift of liquid in a tank such that the aircraft CG is maintained within an established CG offset limit.